Figure 3.

Possible mechanisms for the initiation of endocytosis. (A) Stochastic interactions of adaptors and lipids at the plasma membrane can form a nucleus that recruits further endocytic components. One such assembly that has been proposed is two AP2 complexes along with a clathrin triskelion (Cocucci et al., 2012). (B) Membrane bending may be required or aid in the initiation of endocytosis. Protein domains such as the F-BAR domain have been suggested to induce membrane bending as a mechanism for initiating endocytic site formation (Henne et al., 2010). (C) Clustering of cargo molecules has been shown to be able to induce the assembly of endocytic components de novo (Liu et al., 2010). (D) Specific lipids forming a lipid gradient or at a membrane domain could increase the recruitment of adaptors to the plasma membrane, leading to increased initiation of endocytosis.